It depends on your specific use case. Sometimes the overhead of parallelism overshadows the performance gains. The rule of thumb for any language is to first identify bottlenecks in your code through profiling and optimize accordingly.
For a concrete example, a while ago I was created a program with Clojure which interprets 3D game assets in one format and re-exports them to another format. I needed to run this on thousands of files. After profiling, I found that parallelizing the conversion process for one asset was a red herring as I could barely saturate one thread before it finished. So instead of parallelizing the internals of the conversion process, I found it was much more efficient (and less complex) to just run the conversion process in parallel on many assets at the same time. This meant I could scale the import/export procedure linearly with CPUs, and it was incredibly simple to do with Clojure out of the box without increasing the complexity of the program at all. I know this is a relatively obvious use of parallelism, but my point is that while sometimes it's tempting to try to parallelize things all the way down my experience has taught me that parallelism is often more important at the I/O boundaries of your program, whatever that may be. On Sunday, April 17, 2016 at 5:23:32 PM UTC-4, JvJ wrote: > > Orders of magnitude? Is it even worth running things in parallel in this > case? > > On Sunday, 17 April 2016 07:20:30 UTC-7, tbc++ wrote: >> >> The cost of creating that extra collection will be vastly overshadowed by >> the cost of running pmap. pmap involves the use of several locks, and >> thread co-ordination primitives, these will most likely be orders of >> magnitude more expensive than an extra allocation. >> >> Timothy >> >> On Sun, Apr 17, 2016 at 12:38 AM, JvJ <kfjwh...@gmail.com> wrote: >> >>> Perhaps I should have rephrased. I meant calling it in such a way that >>> the result is a hash map. >>> >>> I know I could do something like: >>> >>> (into a (pmap f a)) >>> >>> This will give the same result, but there's an extra collection in there >>> that I'm not sure is necessary. >>> >>> >>> On Saturday, 16 April 2016 20:15:51 UTC-7, Alex Miller wrote: >>>> >>>> You can call pmap on hash maps! >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To post to this group, send email to clo...@googlegroups.com >>> Note that posts from new members are moderated - please be patient with >>> your first post. >>> To unsubscribe from this group, send email to >>> clojure+u...@googlegroups.com >>> For more options, visit this group at >>> http://groups.google.com/group/clojure?hl=en >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to clojure+u...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> “One of the main causes of the fall of the Roman Empire was that–lacking >> zero–they had no way to indicate successful termination of their C >> programs.” >> (Robert Firth) >> > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
